Literal Tensor Class

An AbstractTensor where all elements have the same constant value. This either arises when using literals in traced code (e.g. x + 1) or when using nv_fill() to create a constant.

Usage

LiteralTensor(data, shape, dtype = default_dtype(data), ambiguous)

Arguments

data

(double(1) | integer(1) | logical(1) | AnvilTensor)
The scalar value or scalarish AnvilTensor (contains 1 element).

shape

(stablehlo::Shape | integer())
The shape of the tensor.

dtype

(stablehlo::TensorDataType)
The data type. Defaults to f32 for numeric, i32 for integer, i1 for logical.

ambiguous

(logical(1))
Whether the type is ambiguous. Ambiguous types usually arise from R literals (e.g., 1L, 1.0) and follow special promotion rules. See the vignette("type-promotion") for more details.

Type Ambiguity

When arising from R literals, the resulting LiteralTensor is ambiguous because no type information was available. See the vignette("type-promotion") for more details.

Lowering

LiteralTensors become constants inlined into the stableHLO program. I.e., they lower to stablehlo::hlo_tensor().

Examples

x <- LiteralTensor(1L, shape = integer(), ambiguous = TRUE)
x
#> LiteralTensor(1, i32?, ()) 
ambiguous(x)
#> [1] TRUE
shape(x)
#> integer(0)
ndims(x)
#> [1] 0
dtype(x)
#> <i32>
# How it appears during tracing:
# 1. via R literals
graph <- trace_fn(function() 1, list())
graph
#> <AnvilGraph>
#>   Inputs: (none)
#>   Body: (empty)
#>   Outputs:
#>     1:f32? 
graph$outputs[[1]]$aval
#> LiteralTensor(1, f32?, ()) 
# 2. via nv_fill()
graph <- trace_fn(function() nv_fill(2L, shape = c(2, 2)), list())
graph
#> <AnvilGraph>
#>   Inputs: (none)
#>   Body:
#>     %1: i32[2, 2] = fill [value = 2, dtype = i32, shape = c(2, 2), ambiguous = FALSE] ()
#>   Outputs:
#>     %1: i32[2, 2] 
graph$outputs[[1]]$aval
#> AbstractTensor(dtype=i32, shape=2x2)